Auto merge of #50546 - kennytm:rollup, r=kennytm

Rollup of 11 pull requests

Successful merges:

 - #49988 (Mention Result<!, E> in never docs.)
 - #50148 (turn `ManuallyDrop::new` into a constant function)
 - #50456 (Update the Cargo submodule)
 - #50460 (Make `String::new()` const)
 - #50464 (Remove some transmutes)
 - #50505 (Added regression function match value test)
 - #50511 (Add some explanations for #[must_use])
 - #50525 (Optimize string handling in lit_token().)
 - #50527 (Cleanup a `use` in a raw_vec test)
 - #50539 (Add more logarithm constants)
 - #49523 (Update RELEASES.md for 1.26.0)

Failed merges:

RELEASES.md

@@ -1,3 +1,209 @@
+Version 1.26.0 (2018-05-10)
+==========================
+
+Language
+--------
+- [Closures now implement `Copy` and/or `Clone` if all captured variables
+  implement either or both traits.][49299]
+- [The inclusive range syntax e.g. `for x in 0..=10` is now stable.][47813]
+- [Stablise `'_`. The underscore lifetime can be used anywhere where a
+  lifetime can be elided.][49458]
+- [`impl Trait` is now stable allowing you to have abstract types in returns
+   or in function parameters.][49255] e.g. `fn foo() -> impl Iterator<Item=u8>` or
+  `fn open(path: impl AsRef<Path>)`.
+- [Pattern matching will now automatically apply dereferences.][49394]
+- [128-bit integers in the form of `u128` and `i128` are now stable.][49101]
+- [`main` can now return `Result<(), E: Debug>`][49162] in addition to `()`.
+- [A lot of operations are now available in a const context.][46882] E.g. You
+  can now index into constant arrays, reference and dereference into constants,
+  and use Tuple struct constructors.
+- [Fixed entry slice patterns are now stable.][48516] e.g.
+  ```rust
+  let points = [1, 2, 3, 4];
+  match points {
+      [1, 2, 3, 4] => println!("All points were sequential."),
+      _ => println!("Not all points were sequential."),
+  }
+  ```
+
+
+Compiler
+--------
+- [LLD is now used as the default linker for `wasm32-unknown-unknown`.][48125]
+- [Fixed exponential projection complexity on nested types.][48296]
+  This can provide up to a ~12% reduction in compile times for certain crates.
+- [Added the `--remap-path-prefix` option to rustc.][48359] Allowing you
+  to remap path prefixes outputted by the compiler.
+- [Added `powerpc-unknown-netbsd` target.][48281]
+
+Libraries
+---------
+- [Implemented `From<u16> for usize` & `From<{u8, i16}> for isize`.][49305]
+- [Added hexadecimal formatting for integers with fmt::Debug][48978]
+  e.g. `assert!(format!("{:02x?}", b"Foo\0") == "[46, 6f, 6f, 00]")`
+- [Implemented `Default, Hash` for `cmp::Reverse`.][48628]
+- [Optimized `str::repeat` being 8x faster in large cases.][48657]
+- [`ascii::escape_default` is now available in libcore.][48735]
+- [Trailing commas are now supported in std and core macros.][48056]
+- [Implemented `Copy, Clone` for `cmp::Reverse`][47379]
+- [Implemented `Clone` for `char::{ToLowercase, ToUppercase}`.][48629]
+
+Stabilized APIs
+---------------
+- [`*const T::add`]
+- [`*const T::copy_to_nonoverlapping`]
+- [`*const T::copy_to`]
+- [`*const T::read_unaligned`]
+- [`*const T::read_volatile`]
+- [`*const T::read`]
+- [`*const T::sub`]
+- [`*const T::wrapping_add`]
+- [`*const T::wrapping_sub`]
+- [`*mut T::add`]
+- [`*mut T::copy_to_nonoverlapping`]
+- [`*mut T::copy_to`]
+- [`*mut T::read_unaligned`]
+- [`*mut T::read_volatile`]
+- [`*mut T::read`]
+- [`*mut T::replace`]
+- [`*mut T::sub`]
+- [`*mut T::swap`]
+- [`*mut T::wrapping_add`]
+- [`*mut T::wrapping_sub`]
+- [`*mut T::write_bytes`]
+- [`*mut T::write_unaligned`]
+- [`*mut T::write_volatile`]
+- [`*mut T::write`]
+- [`Box::leak`]
+- [`FromUtf8Error::as_bytes`]
+- [`LocalKey::try_with`]
+- [`Option::cloned`]
+- [`btree_map::Entry::and_modify`]
+- [`fs::read_to_string`]
+- [`fs::read`]
+- [`fs::write`]
+- [`hash_map::Entry::and_modify`]
+- [`iter::FusedIterator`]
+- [`ops::RangeInclusive`]
+- [`ops::RangeToInclusive`]
+- [`process::id`]
+- [`slice::rotate_left`]
+- [`slice::rotate_right`]
+- [`String::retain`]
+
+
+Cargo
+-----
+- [Cargo will now output path to custom commands when `-v` is
+  passed with `--list`][cargo/5041]
+- [The Cargo binary version is now the same as the Rust version][cargo/5083]
+- [`Cargo.lock` files are now included in published crates.][cargo/5093]
+
+Misc
+----
+- [The second edition of "The Rust Programming Language" book is now recommended
+  over the first.][48404]
+
+Compatibility Notes
+-------------------
+
+- [aliasing a `Fn` trait as `dyn` no longer works.][48481] E.g. the following
+  syntax is now invalid.
+  ```
+  use std::ops::Fn as dyn;
+  fn g(_: Box<dyn(std::fmt::Debug)>) {}
+  ```
+- [The result of dereferences are no longer promoted to `'static`.][47408]
+  e.g.
+  ```rust
+  fn main() {
+      const PAIR: &(i32, i32) = &(0, 1);
+      let _reversed_pair: &'static _ = &(PAIR.1, PAIR.0); // Doesn't work
+  }
+  ```
+- [Deprecate `AsciiExt` trait in favor of inherent methods.][49109]
+- [`".e0"` will now no longer parse as `0.0` and will instead cause
+  an error.][48235]
+- [Removed hoedown from rustdoc.][48274]
+- [Bounds on higher-kinded lifetimes a hard error.][48326]
+
+[46882]: https://github.com/rust-lang/rust/pull/46882
+[47379]: https://github.com/rust-lang/rust/pull/47379
+[47408]: https://github.com/rust-lang/rust/pull/47408
+[47813]: https://github.com/rust-lang/rust/pull/47813
+[48056]: https://github.com/rust-lang/rust/pull/48056
+[48125]: https://github.com/rust-lang/rust/pull/48125
+[48166]: https://github.com/rust-lang/rust/pull/48166
+[48235]: https://github.com/rust-lang/rust/pull/48235
+[48274]: https://github.com/rust-lang/rust/pull/48274
+[48281]: https://github.com/rust-lang/rust/pull/48281
+[48296]: https://github.com/rust-lang/rust/pull/48296
+[48326]: https://github.com/rust-lang/rust/pull/48326
+[48359]: https://github.com/rust-lang/rust/pull/48359
+[48404]: https://github.com/rust-lang/rust/pull/48404
+[48481]: https://github.com/rust-lang/rust/pull/48481
+[48516]: https://github.com/rust-lang/rust/pull/48516
+[48628]: https://github.com/rust-lang/rust/pull/48628
+[48629]: https://github.com/rust-lang/rust/pull/48629
+[48657]: https://github.com/rust-lang/rust/pull/48657
+[48735]: https://github.com/rust-lang/rust/pull/48735
+[48978]: https://github.com/rust-lang/rust/pull/48978
+[49101]: https://github.com/rust-lang/rust/pull/49101
+[49109]: https://github.com/rust-lang/rust/pull/49109
+[49121]: https://github.com/rust-lang/rust/pull/49121
+[49162]: https://github.com/rust-lang/rust/pull/49162
+[49184]: https://github.com/rust-lang/rust/pull/49184
+[49234]: https://github.com/rust-lang/rust/pull/49234
+[49255]: https://github.com/rust-lang/rust/pull/49255
+[49299]: https://github.com/rust-lang/rust/pull/49299
+[49305]: https://github.com/rust-lang/rust/pull/49305
+[49394]: https://github.com/rust-lang/rust/pull/49394
+[49458]: https://github.com/rust-lang/rust/pull/49458
+[`*const T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add
+[`*const T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping
+[`*const T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to
+[`*const T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned
+[`*const T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile
+[`*const T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read
+[`*const T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub
+[`*const T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add
+[`*const T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub
+[`*mut T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add-1
+[`*mut T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping-1
+[`*mut T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to-1
+[`*mut T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned-1
+[`*mut T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile-1
+[`*mut T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read-1
+[`*mut T::replace`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.replace
+[`*mut T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub-1
+[`*mut T::swap`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.swap
+[`*mut T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add-1
+[`*mut T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub-1
+[`*mut T::write_bytes`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_bytes
+[`*mut T::write_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_unaligned
+[`*mut T::write_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_volatile
+[`*mut T::write`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write
+[`Box::leak`]: https://doc.rust-lang.org/std/boxed/struct.Box.html#method.leak
+[`FromUtf8Error::as_bytes`]: https://doc.rust-lang.org/std/string/struct.FromUtf8Error.html#method.as_bytes
+[`LocalKey::try_with`]: https://doc.rust-lang.org/std/thread/struct.LocalKey.html#method.try_with
+[`Option::cloned`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.cloned
+[`btree_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/btree_map/enum.Entry.html#method.and_modify
+[`fs::read_to_string`]: https://doc.rust-lang.org/std/fs/fn.read_to_string.html
+[`fs::read`]: https://doc.rust-lang.org/std/fs/fn.read.html
+[`fs::write`]: https://doc.rust-lang.org/std/fs/fn.write.html
+[`hash_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html#method.and_modify
+[`iter::FusedIterator`]: https://doc.rust-lang.org/std/iter/trait.FusedIterator.html
+[`ops::RangeInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html
+[`ops::RangeToInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html
+[`process::id`]: https://doc.rust-lang.org/std/process/fn.id.html
+[`slice::rotate_left`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_left
+[`slice::rotate_right`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_right
+[`String::retain`]: https://doc.rust-lang.org/std/string/struct.String.html#method.retain
+[cargo/5041]: https://github.com/rust-lang/cargo/pull/5041
+[cargo/5083]: https://github.com/rust-lang/cargo/pull/5083
+[cargo/5093]: https://github.com/rust-lang/cargo/pull/5093
+
+
 Version 1.25.0 (2018-03-29)
 ==========================
 

src/liballoc/lib.rs

@@ -125,6 +125,7 @@
 #![feature(inclusive_range_methods)]
 #![cfg_attr(stage0, feature(generic_param_attrs))]
 #![feature(rustc_const_unstable)]
+#![feature(const_vec_new)]
 
 #![cfg_attr(not(test), feature(fn_traits, i128))]
 #![cfg_attr(test, feature(test))]

src/liballoc/raw_vec.rs

@@ -748,7 +748,7 @@ mod tests {
 
     #[test]
     fn allocator_param() {
-        use allocator::{Alloc, AllocErr};
+        use alloc::AllocErr;
 
         // Writing a test of integration between third-party
         // allocators and RawVec is a little tricky because the RawVec

src/liballoc/str.rs

@@ -207,7 +207,8 @@ impl str {
     /// let s = "this is old";
     /// assert_eq!(s, s.replace("cookie monster", "little lamb"));
     /// ```
-    #[must_use]
+    #[must_use = "this returns the replaced string as a new allocation, \
+                  without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn replace<'a, P: Pattern<'a>>(&'a self, from: P, to: &str) -> String {
@@ -247,7 +248,8 @@ impl str {
     /// let s = "this is old";
     /// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));
     /// ```
-    #[must_use]
+    #[must_use = "this returns the replaced string as a new allocation, \
+                  without modifying the original"]
     #[stable(feature = "str_replacen", since = "1.16.0")]
     pub fn replacen<'a, P: Pattern<'a>>(&'a self, pat: P, to: &str, count: usize) -> String {
         // Hope to reduce the times of re-allocation

src/liballoc/string.rs

@@ -380,7 +380,8 @@ impl String {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn new() -> String {
+    #[rustc_const_unstable(feature = "const_string_new")]
+    pub const fn new() -> String {
         String { vec: Vec::new() }
     }
 

src/libcore/fmt/builders.rs

@@ -84,7 +84,7 @@ impl<'a> fmt::Write for PadAdapter<'a> {
 /// // prints "Foo { bar: 10, baz: "Hello World" }"
 /// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() });
 /// ```
-#[must_use]
+#[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub struct DebugStruct<'a, 'b: 'a> {
@@ -181,7 +181,7 @@ impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
 /// // prints "Foo(10, "Hello World")"
 /// println!("{:?}", Foo(10, "Hello World".to_string()));
 /// ```
-#[must_use]
+#[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub struct DebugTuple<'a, 'b: 'a> {
@@ -319,7 +319,7 @@ impl<'a, 'b: 'a> DebugInner<'a, 'b> {
 /// // prints "{10, 11}"
 /// println!("{:?}", Foo(vec![10, 11]));
 /// ```
-#[must_use]
+#[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub struct DebugSet<'a, 'b: 'a> {
@@ -390,7 +390,7 @@ impl<'a, 'b: 'a> DebugSet<'a, 'b> {
 /// // prints "[10, 11]"
 /// println!("{:?}", Foo(vec![10, 11]));
 /// ```
-#[must_use]
+#[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub struct DebugList<'a, 'b: 'a> {
@@ -461,7 +461,7 @@ impl<'a, 'b: 'a> DebugList<'a, 'b> {
 /// // prints "{"A": 10, "B": 11}"
 /// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)]));
 /// ```
-#[must_use]
+#[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub struct DebugMap<'a, 'b: 'a> {

src/libcore/mem.rs

@@ -959,8 +959,9 @@ impl<T> ManuallyDrop<T> {
     /// ManuallyDrop::new(Box::new(()));
     /// ```
     #[stable(feature = "manually_drop", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_manually_drop_new")]
     #[inline]
-    pub fn new(value: T) -> ManuallyDrop<T> {
+    pub const fn new(value: T) -> ManuallyDrop<T> {
         ManuallyDrop { value: value }
     }
 

src/libcore/num/f32.rs

@@ -128,10 +128,18 @@ pub mod consts {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
 
+    /// log<sub>2</sub>(10)
+    #[unstable(feature = "extra_log_consts", issue = "50540")]
+    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
+
     /// log<sub>10</sub>(e)
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
 
+    /// log<sub>10</sub>(2)
+    #[unstable(feature = "extra_log_consts", issue = "50540")]
+    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
+
     /// ln(2)
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;

src/libcore/num/f64.rs

@@ -124,10 +124,18 @@ pub mod consts {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const E: f64 = 2.71828182845904523536028747135266250_f64;
 
+    /// log<sub>2</sub>(10)
+    #[unstable(feature = "extra_log_consts", issue = "50540")]
+    pub const LOG2_10: f64 = 3.32192809488736234787031942948939018_f64;
+
     /// log<sub>2</sub>(e)
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const LOG2_E: f64 = 1.44269504088896340735992468100189214_f64;
 
+    /// log<sub>10</sub>(2)
+    #[unstable(feature = "extra_log_consts", issue = "50540")]
+    pub const LOG10_2: f64 = 0.301029995663981195213738894724493027_f64;
+
     /// log<sub>10</sub>(e)
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const LOG10_E: f64 = 0.434294481903251827651128918916605082_f64;

src/libcore/result.rs

@@ -251,7 +251,7 @@ use ops;
 /// [`Ok`]: enum.Result.html#variant.Ok
 /// [`Err`]: enum.Result.html#variant.Err
 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Debug, Hash)]
-#[must_use]
+#[must_use = "this `Result` may be an `Err` variant, which should be handled"]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub enum Result<T, E> {
     /// Contains the success value

src/libcore/tests/num/flt2dec/random.rs

@@ -11,7 +11,6 @@
 #![cfg(not(target_arch = "wasm32"))]
 
 use std::i16;
-use std::mem;
 use std::str;
 
 use core::num::flt2dec::MAX_SIG_DIGITS;
@@ -75,8 +74,7 @@ pub fn f32_random_equivalence_test<F, G>(f: F, g: G, k: usize, n: usize)
     let mut rng: XorShiftRng = Rand::rand(&mut rand::thread_rng());
     let f32_range = Range::new(0x0000_0001u32, 0x7f80_0000);
     iterate("f32_random_equivalence_test", k, n, f, g, |_| {
-        let i: u32 = f32_range.ind_sample(&mut rng);
-        let x: f32 = unsafe {mem::transmute(i)};
+        let x = f32::from_bits(f32_range.ind_sample(&mut rng));
         decode_finite(x)
     });
 }
@@ -87,8 +85,7 @@ pub fn f64_random_equivalence_test<F, G>(f: F, g: G, k: usize, n: usize)
     let mut rng: XorShiftRng = Rand::rand(&mut rand::thread_rng());
     let f64_range = Range::new(0x0000_0000_0000_0001u64, 0x7ff0_0000_0000_0000);
     iterate("f64_random_equivalence_test", k, n, f, g, |_| {
-        let i: u64 = f64_range.ind_sample(&mut rng);
-        let x: f64 = unsafe {mem::transmute(i)};
+        let x = f64::from_bits(f64_range.ind_sample(&mut rng));
         decode_finite(x)
     });
 }
@@ -105,7 +102,8 @@ pub fn f32_exhaustive_equivalence_test<F, G>(f: F, g: G, k: usize)
     // iterate from 0x0000_0001 to 0x7f7f_ffff, i.e. all finite ranges
     let (npassed, nignored) = iterate("f32_exhaustive_equivalence_test",
                                       k, 0x7f7f_ffff, f, g, |i: usize| {
-        let x: f32 = unsafe {mem::transmute(i as u32 + 1)};
+
+        let x = f32::from_bits(i as u32 + 1);
         decode_finite(x)
     });
     assert_eq!((npassed, nignored), (2121451881, 17643158));